Apparatus for splicing thermoplastic yarn by high frequency vibrations



y 1965 F. P. STROTHER APPARATUS FOR SPLICING THERMOPLASTIC YARN BY HIGHFREQUENCY VIBRATIONS Original Filed Feb. 28, 1962 .2 Sheets-Sheet 1 FIG.4.

INVENIOR i550 Z? Swan EA BY W WM.

ATTORNEYS May 18, 1965 F. P. STROTHER ,1

APPARATUS FOR SPLICING THERMOPLASTIC YARN BY HIGH FREQUENCY VIBRATIONSOriginal Filed Feb. 28, 1962 2 Sheets-Sheet 2 no 10 68 4 F1625. I 66 I2FIG. 7.

7 46 m FREQ- i"2 TRANSDUCER 1 GENERATOR s TIME DELAY k CIRCUIT BREAKER:2 I

FIG. 6

,re :2 3 Z64 TRANS DUCER 2 eenenm'on 9a L92 Fig.9. f L 1' m2 INVENTOR96/ t fl0P5rR0rHfi M, m BY Q:M/

ATTORNEYS United States Patent Ofifice 3,134,363 Fatented May 18, 196510 Claims. (Cl. 156-433) This invention relates to the splicing ofyarns, and in particular to the splicing of yarns composed of multiplefibers or filaments of synthetic, thermoplastic material. The inventioninvolves an apparatus for splicing yarns by means of pressure and highfrequency vibrations. This application is a division of my copendingapplication Serial No. 176,246, filed February 28, 1962.

In textile operations utilizing continuous yarns, such as in tufting,yarn lengths are commonly spliced one to another by knotting orcementing. Knot splices are bulky and pass through guides, needle eyesand the like only with difiiculty, while cemented splices requiresetting or drying time, and the adhesive used therein is prone to stickto machinery and interfere with free operation. In ordinary use,cemented splices pick up dirt and appear in the finished product asunsightly defects. These and other conventional splices, accordingly,involve significant disadvantages.

A principal object of the present invention is to provide a method ofsplicing multifilament yarns, such as carpet yarns, by means of highfrequency vibrations, which is easily and quickly accomplished, andresults in a small splice of substantially circular cross section,usually smaller than the normal free diameter of the yarn.

Another object of the invention is the provision of a method andapparatus for making novel yarn splices which are strong, stable andsecure, uniform and inconspicuous, and capable of passing throughguides, eyes, etc., smoothly and without difficulty. The inventioneffects splices in which the dye characteristics of the yarn portionsjoined in the splice are unchanged, whereby the splices remaininconspicuous in the finished product.

A related object of the invention is to provide a simple, portable anddurable device for splicing yarns, which requires little effort or skillon the part of the operator, and is almost completely automatic inoperation.

Another object is to provide a method of bonding multifilamcnt yarns bythe combined effect of solvation agents and ultrasonic energy to providesplies of exceptional strength. Further objects will be in part evidentand in part pointed out hereinafter.

The invention and the novel features thereof may best be made clear fromthe following description and the accompanying drawings, in which:

FEGURE 1 is a sectional view illustrative of the invention, showing twoyarns positioned in a die and the tool utilized in splicing;

FIGURE 2 is a sectional view corresponding generally to FIGURE 1, butshowing tool and the die in final position, wherein the yarns arespliced;

FIGURE 3 is an elevational view of two yarns spliced in accordance withthe invention;

FIGURE 4 is an elevational view of an illustrative embodiment of adevice or a device incorporating the present invention, with automaticfeatures for closing and opening the energizing circuit thereof;

FlGURE 5 is a sectional view of a portion of the device of FIGURE 4,showing details of the die and its mounting;

FIGURE 6 is a sectional view taken on the line 6-6 of FIGURE 4,illustrating constructional details of the die and tool;

FIGURE 7 is a simplified circuit diagram illustrating one energizingcircuit for the splicing device;

FIGURE 3 is a simplified circuit diagram illustrating another energizingcircuit for the device, and

FIGURE 9 is a diagrammatic illustration of a modified tool and die form,adapted to produce a splice which requires no trimming.

Referring to the drawings, in FIGURE 1 is shown a die it? of metal orthe like provided with a slot 12, the bottom lid of which is concave andsubstantially semicylindrical, as shown. The surface 14 or the centralportion thereof is pre erably in the form of a circular cylinder, butmay be otherwise shaped or formed, if desired.

Positioned in slot 14 are yarns 16 and 18, which are composed ofmultiple fibers or filaments of synthetic, thermoplastic material, suchas polyesters, polyamides, polyethylene, polypropylene, polyvinylchloride, Saran and mixtures thereof. The width of the slot 12, it willbe noted, is somewhat smaller than the normal free diameter of theyarns, whereby the latter are flattened somewhat in the die slot, asshown. The tool 2!) is adapted to enter and fit closely the die slot 12,and the tool face 22 is concave, substantially semi-cylindrical at leastin the central portion thereof, and generally complementary to the slotbottom 14.

In accordance with the invention, tool 20 is advanced and urged into thedie slot 12, whereby the yarns 16 and 13 are compressed between the diesurface 14 and the tool face 22 and the tool is then vibrated at highfrequency, preferably in the ultrasonic range. The compression of theyarns compacts them to the extent that the fiber or filament surfacesthereof touch, and the ultrasonic energy applied through the tool, inline with the arrow 24 of FIGURE 2, produces heating by interfiber and/or intermolecular friction, causing the fibers or filaments of the yarnsto soften, compact and bond to each other, whereby an excellent andpermanent bond or splice 26 is effected.

This method is particularly adapted to the bonding of multifilamentyarns, and it appears that the application of ultrasonic energy theretocauses interfiber friction which leads to joining of the fiber surfaces.This is particularly advantageous in that the dye characteristics of theyarns so joined are substantially unchanged, and the spliced yarns maybe dyed in any common manner without producing any variation in color orshade in the spliced area. It is for this reason desirable to controland limit the quantity of energy applied to the yarns during thesplicing operation. As will be evident, excessive application or energymay effect a splice constituting a substantially solid center section orbody of material, which would not accept dye in the manner of theadjoining yarns, and would accordingly be conspicuous in the finishedproduct. Moreover, if the splice is virtually solidified, high stresspoints would exist in the junctions between the individual fibers andthe solidified mass, and a materially weaker splice would result.

A completed splice is illustrated in FIGURE 3, and it will be evidentthat the tag ends 28 and 39, of the yarns 16 and 13 respectively, may beclipped from the completed splice, as along the dotted lines 32 and 34.As shown, the splice 26 is substantially uniformly compacted and roundin cross section, and somewhat smaller than the normal free diameter ofthe yarns of which it is composed. Being permanently bonded, it is proofagainst separation, unraveling and the like. Since the splice containsno foreign material such as latex, it offers no impediment to processingof the yarn, and has no more tendency to attract and hold dirt than anyother section of the yarn, whereby it will not become a conspicuouscenter of soil.

An exemplary splicing device embodying the present invention isillustrated in FIGURE 4, and comprises a supthe end of the transducerfacing lug 44 extends the usual transformer section 48, and the tool 20is mounted at the outer end thereof. The tool, for reasons presentlyapparent, is preferably removable and replaceable,and may be removablymounted in the transformer section in any conventional manner, asby'means of screw threads. In.-

side the lug 44 is mounted the die 10, with its slot 12 fac-' ing andaligned with the tool 20.

Means are provided to advance the transducer and tool 7 7 toward andinto the die 10. As shown, a rack 50 is fixedly associated with thetransducer 46, and a trigger member 52 is pivotally mounted at 54 on theside of the support member 40, the upper end of the trigger member beingformed intoa gear segment 56 positioned and adapted to engage the rack50. Suitable means, such as the stop lug 58 on the trigger member 52, isprovided to limit the rearward movement of the transducer 46, and aresilient element such as spring 60 may be provided to urge thetransducer rearwardly, that is away from the die 10. As shown, thespring 60 is fixed to the support member 40 and the rack 50 of thetransducer, and extends 'therebetween. Conductors 62 are provided toconduct a high frequency alternating electriccurrent from a source ofsupply, which may be a high. frequency generator, to the support member40, and flexible conductors 64 are pro-' vided to conduct the currentfrom the support member 40 to the transducer 46, it being understoodthat the conductors 62 and 64 are series connected.

To splice yarns, two respective yarn endsmay be positioned by theoperator in the slot 12 of the die 10, preferably in opposedrelationship, and the transducer 46 and the tool 20 carried thereby areadvanced until the tool enters the die slot and compresses the yarns tothe extent". i

that their fibers or filaments are generally in contact. As will beevident, the tool may remain stationary While the die is displacedtheretoward, or both elements may be moved with respect to each other.In theillustrative embodiment, the transducer and. tool may be advancedby pivoting the trigger member 52 toward the pistol grip 42, extendingthe spring 60. When the yarns are sufliciently compressed between thetool and the die, the energizing circuit of the transducer may beclosed, whereupon the transducer creates ultrasonic waves or vibrationswhich are transmitted by the transformer section to the tool, which inturn applies ultrasonic energy to the compressed yarns, to the end thatthe fibers or filaments thereof are softened, compacted and securelybonded to each other.

Depending on the size and character of the yarn, the application ofenergy may extend for from less'than one second to about ten seconds ormore, whereupon the energizing circuit may be opened and the toolwithdrawn. The completed splice may be removed from the die slot,

and any extending tag ends clipped therefrom. The splic-. 1

ing operation is more effective, it has been found, if the yarns areuntensioned during splicing. This appears to. be

due to the tendency of some fibers to neck down if tensioned during theapplication of energy thereof, resultin in weakened yarn sectionsadjoining the splice.

Further to prevent undesired weakening of the yarn sections adjoiningthe splice, it has been found desirable to flare or round of: the yarnengaging surfaces at'their outer ends in such a manner that thetransition from the splice to the adjoining yarn sections is gradual.For this purpose, as shown in FIGURE 6, the tool face 22 and the slotbottom 14, at the longitudinal .ends thereof, may be outwardly roundedand flared as at 23 and 15, respectively.

The transducer'may 'nera'lly from about 20 ,000 to about 5 0,000 cyclesper Lample, if the normal freediameter of the yarn is in the range of.050 inch, the width of the dieslot andtool may be .040 inch. The otherdimension of the tool, corresponding to the length of the spliceeffected, may by way of example be .125 inch. 7

As another feature of the invention, means may be provided to automatethe splicing operation, and to limit the energy and/ or pressure appliedto the yarns to' prevent excessive'solidification thereof. For example,means may be provided to automatically close the transducer ene'rg'izingcircuit when'the force'or pressure exerted by the tool 20 againstthe'die 10 through the compressed yarns reaches a predetermined value.As shown in FIGURES 4 and 5, the support member lug 44 is apertured at66, and the die 10 is provided with an outwardly extending guide pin 68adapted to fit and extend through the lug aperture 66. The inner face oflug 44 is provided with a plurality of small leaf springs 70, adapted toengage and normally space the die from'the lug, and a small normallyopen switch 72 is mounted by means of bracket 74 on the outer face oflug 44, in such position that when the die 10 is displaced to the rightfrom the position shown in FIGURE 5, deflecting the springs 70, theouter end of pin 68 will engage and close switch 72. In this manner, andthrough proper design and adjustment of spring 70, the transducerenergizing circuit may be closed when force or pressure of apredetermined value is exerted against the die by the tool through thecompressed yarns, the pres- .sure being sufficient to deflect springsand displacethe die to close the switch; 7 V a V The energizing circuitfor the transducer may then be as illustrated in FIGURE '7, whereinconductors 76 lead .from a source of low frequency alternating currentto element, and is preferably adjustable. 'In this manner,

the timing of the splicing operation may be entirely automatic. Theoperator need only position the yarns to be spliced in the die slot, andurge the tool thereinto. When the pressure exerted through thecompressed yarns reaches the predetermined value, the energizing circuitwill be automatically closed, and then will be automatically openedafter a predetermined interval. The resultant V splices will be quiteuniform.

In place of a time delay circuit breaker to open the transducerenergizing circuit, means may be provided to open the circuit when theentry of thetool into the die slot reaches a predetermined limit. Itwillbe understood that while the yarns are initially compressed betweenthe tocl and die, upon thelapplicationof high frequency vibrationsthereto the yarns are further compacted, and

'the extent of such further compaction may be utilized as a practicallimit. to terminate the splicing operation. This may be readily. andsimply accomplished, as illustrated in FIGURE '4, by providing anextension 82 on therack 50, whereby it is rigidly associated withthetransducer and its tool, andmounting a normally closed switch 84 on the.support member 40, as by means of bracket 86, the switch .84 beingpositioned so that it will be engaged and opened bythe rack extension82'when the tool 20 reaches the preselected position-in the die slot 12..In this case, the .transducer energizingcircuit maybe as illustrated inFIGURE 8, wherein conductors 76-lead from a source of low frequencyelectrical current to the high frequency generator 78, and highfrequency alternating current is .a small pivotal latch 88 in supportmember 40, the latch being urged outwardly to the position shown by asmall leaf spring 90. As will be evident, the latch 88 may be readilypressed inwardly, deflecting spring 90, to clear the die 10, which maythen be withdrawn over the latch from the lug aperture 66, and a die ofsimilar dimension-s, although with a different die slot, may readily besubstituted. When the die is in position, in contact with leaf spring 74the latch serves to retain the die in place, and prevent furthermovement away from the support member lug 44. As previously indicated,the tool may be replaceable in the transducer transformer section 48, sothat if a die of materially different slot width is substituted, a toolof similar width may also be substituted. As will be evident, means mayalso be provided for slight adjustment of the switch 84, toward and awayfrom the rack extension 32, so that the limit of entry of the tool intothe die slot effective to open the transducer energizing circuit may bevaried as desired.

The device may be employed to splice three or more yarns, if desired,and also to splice yarns of synthetic, thermoplastic material to yarnsof other material. A nylon yarn may be spliced to a cotton yarn, forexample, although in such case it is usually necessary to apply greaterpressure, and for a greater length of time, to attain an effectivesplice. Similarly, non-thermoplastic yarns may be spliced to each other,with the aid of a short piece of thermoplastic yarn. In this manner, ashort piece of nylon yarn may be sandwiched between two cotton yarns,and the assembly spliced in the manner described.

It is known to join fibers and yarns through the action of solvationagents, by which is meant materials effective to soften and/or swell thesurfaces of fibers. The solvation action of these materials is commonlyassisted by means of pressure and/ or heat. For example, zinc chloride,zinc bromide and ferric chloride are effective solvation agents fornylon fibers. Calcium and magnesium thiocyanates are effective solvationagents for polyester fibers, such as polyethylene terephthalate soldunder the trademark Dacron. It has been found that exceptionally strongsplices can be effected in accordance with the present invention, bytreating the yarn sections to be spliced with an appropriate 'solvantionagent, immediately prior to the application of ultrasonic energythereto.

In accordance with another aspect of the invention, the tool or die formmay be modified to automatically shear the yarn ends in the course ofthe splicing operation, and thereby produce a splice requiring nosubsequent trimming. As diagrammatically illustrated in FIGURE 9, thedie '91 may be provided with an outwardly extending lug 92, offsetlaterally from the die working face 94. The associated tool 96 will becoextensive with the working face 94 of the die, as shown. For splicingin accordance with this tool and die form, the yarn-s 98 and 190 arearranged in parallel relationship with ends extending in the samedirection. In such case, if ultrasonic energy is applied to the tool atthe initiation of the advance of the tool and die toward each other, theyarns will be sheared along the dotted line 102, between the lug 92 andthe adjacent end of tool 96, as the elements approach splicing position,and the resultant splice will be free of tag ends. This manner ofsplicing is particularly advantageous when the necessity for maintainingthe spliced yarn in linear arrangement is not critical. In all otherrespects, the splicing in accordance with this practice may be effectedb in accordance with the procedures and embodiments described above.

It will thus be seen that there has been provided by this inventionapparatus in which the various objects hereinbefore set forth, togetherwith many practical advantages, are successfully achieved. As variouspossible embodiments may be made of the several features of the aboveinvention, all without departing from the scope thereof, it is to beunderstood that all matter hereinbefore set 'forth or shown in theaccompanying drawings is to be interpreted as illustrative, and not in alimiting sense.

I claim:

1. Apparatus for splicing yarns containing thermoplastic materialcomprising a die having a slot therein, the bottom of said slot beingconcave and substantially semi-cylindrical, a tool adapted to enter saidslot, the face of said tool being concave, substantially semi-cylindrical, and generally complementary to the slot bottom, means for urgingsaid tool into said die slot, and means for vibrating said tool at highfrequency.

2. Apparatus as defined in claim 1, wherein said slot bottom and saidtool face are outwardly flared at the longitudinal ends thereof.

3. Apparatus for splicing yarns containing thermoplastic materialcomprising a die having a slot therein, a tool adapted to enter saidslot, a transducer operatively associated with said tool, an energizingcircuit for said transducer, means for urging said tool into said dieslot, and means for opening the transducer circuit when the entry ofsaid tool into said die slot reaches a predetermined limit.

4. Apparatus for splicing yarns containing thermoplastic materialcomprising a die having a slot therein, a tool adapted to enter saidslot, a transducer operatively associated with said tool, an energizingcircuit for said transducer, means for urging said tool into said dieslot, and pressure responsive means associated with said die for closingthe transducer circuit.

5. Apparatus for splicing yarns containing thermoplastic materialcomprising a die having a slot therein, a tool adapted to enter saidslot, a transducer operatively associated with said tool, an energizingcircuit for said transducer, means for urging said tool into said dieslot, pressure responsive means associated with said die for closing thetransducer circuit, and time delay breaker means for opening thetransducer circuit.

6. Apparatus for splicing yarns containing thermoplastic materialcomprising a die having a slot therein, the bottom of said slot beingconcave and substantially semi-cylindrical, a tool adapted to enter saidslot, the face of said tool being concave, substantiallysemi-cylindrical, and generally complementary to the slot bottom, atransducer operatively associated with said tool, an energizing circuitfor said transducer, means for urging said tool into said die slot, andmeans for opening the transducer circuit when the entry of said toolinto said die slot reaches a predetermined limit.

7. Apparatus for splicing yarns containing thermoplastic materialcomprising a die having a slot therein, the bottom of said slot beingconcave and substantially semi-cylindrical, a tool adapted to enter saidslot, the face of said tool being concave, substantiallysemi-cylindrical, and generally complementary to the slot bottom, atransducer operatively associated with said tool, an energizing circuitfor said transducer, means for urging said tool into said die slot, andpressure responsive means associated with said die for closing thetransducer circuit.

8. Apparatus for splicing yarns containing thermoplastic materialcomprising a die having a slot therein, the bottom of said slot beingconcave and substantially semi-cylindrical, a tool adapted to enter saidslot, the face of said tool being concave, substantiallysemi-cylindrical, and generally complementary to the slot bottom, atransducer operatively associated with said tool, an en- 'ergizing'circuit for said transducer, means for urging said tool into said dieslot, pressure responsive means associated with said die for closing thetransducer circuit, and time delay breaker means for opening the trans-.ducer circuit.

9. Apparatus for splicing yarns containing thermoplastic materialcomprising'a die having a slot therein,

the bottom of said slot being concave and substantiallysemi-cylindrical, a tool adapted to enter said slot, the

face of said tool being concave, substantially semi-cylindrical, andgenerally complementary to the slot bottom,

a transducer operatively associated with said tool, an

energizing circuit for said transducer, means for urging said tool intosaid die slot, pressure responsive means associated with said die forclosing the transducer circuit, and means for opening the transducercircuit when the entry of said tool into said die slot reaches apredetermined limit. 7

tool may enter. said die slot, means for urging said transducer and tooltoward said die, and an for said transducer.

energizing circuit vReferences'Cited by the Examiner UNITED STATESPATENTS "2,514,is'4 7/50 Lower 1 56-158 2,514,197 7/50' Groten etal.'156158 2,617,914 11/52 Keller et a1; 1s6 s02 XR EARL M. BERGERT,Primary Examiner.

1. APPARATUS FOR SPLICING YARNS CONTAINING THERMOPLASTIC MATERIALCOMPRISING A DIE HAVING A SLOT THEREIN THE BOTTOM OF SAID SLOT BEINGCONCAVE AND SUBSTANTIALLY SEMI-CYLINDRICAL, A TOOL ADAPTED TO ENTER SAIDSLOT, THE FACE OF SAID TOOL BEING CONCAVE, SUBSTANTIALLYSEMI-CYLINDRICAL, AND GENERALLY COMPLEMENTARY TO THE SLOT BOTTOM, MEANSFOR URGING SAID TOOL INTO SAID DIE SLOT, AND MEANS FOR VIBRATING SAIDTOOL AT HIGH FREQUENCY.